Notes & Comments

Short Biography of Navier

After losing his father – a lawyer in Dijon – at the age of just 14, the young Navier was cared for by his uncle and his wife, Emil and Marie Gauthey. Emil Gauthey taught part-time at the École des Ponts et Chaussées and in 1791 was appointed general inspector of the Bridges & Highways Corps. Navier’s uncle therefore became his role model. He studied at the École Polytechnique and École des Ponts et Chaussées from 1802 to 1806 and afterwards, in addition to practical employment in bridge-building, dedicated himself to preparing a new edition of Gauthey’s Traité des ponts (1813) and Bélidor’s engineering manuals [Bélidor, 1813], [Bélidor, 1819]. In 1819 he was appointed professeur suppléant at the École des Ponts et Chaussées which resulted in his Leçons [Navier, 1820]. During the early 1820s, Navier established the principles of elastic theory together with Cauchy and Lamé. In May 1821 Navier submitted a paper to the Académie des Sciences in which he derived the basic equations of elastic theory (to be named after him and Lamé) from the discontinuum (molecular) hypothesis; an extract from this paper was published in 1823 [Navier, 1823/3], but publication of the complete work had to wait until 1827 [Navier, 1827]. The year 1828 was marked by a dispute between Navier and Denis Poisson (1781–1840) in the journal Annales de Chimie et de Physique concerning the principles of elastic theory, which, however, did not supply any clarification because both based their ideas on the molecular hypothesis. Navier was commissioned by the government to travel to England and Scotland in order to find out about the construction of chain suspension bridges; his findings were published in his famous Rapport, which contained the first theory of suspension bridges [Navier, 1823/1]. Although this publication earned him membership of the Académie in 1824, its implementation in practice resulted in numerous difficulties for Navier in connection with his failed Pont des Invalides suspension bridge project [Stüssi, 1940, p. 204]. At the same time, the 1820s can be seen as his most creative years. His Résumé des Leçons [Navier, 1826] made Navier the founder of theory of structures; this work was to challenge great minds in the establishment phase of structural theory – like Saint-Venant, who obtained a copy of the third edition and improved on it by adding a grandiose historicocritical commentary [Navier, 1864]. In Germany, Moritz Rühlmann in particular is credited with establishing Navier’s theory of structures [Navier, 1851/1878]. Navier became Cauchy’s successor at the chair of analysis and mechanics at the École Polytechnique, Chevalier de la la Légion d’Honneur and section inspector of the Bridges & Highways Corps – all in 1831. In sociological terms, Navier – like Clapeyron and other prominent scientists and engineers – was committed to the ideas of Saint-Simon and his followers. Therefore, Navier nominated Auguste Comte as his assistant at the École Polytechnique and played an active part in events in Raucourt de Charleville’s Institut de la Morale Universelle [McKeon, 1981, p. 2]. In this way the classical engineering sciences established in France at that time – in the first place theory of structures and applied mechanics – experienced an implicit sociological significance on which the, as it were, natural positivism of the engineering scientist dedicated to the “scientific paradigms” [Ropohl, 1999, pp. 20–23] could draw sustenance.